1. Field of the invention
This invention relates to an apparatus for spreading and flattening the end seal area of vertical form-fill-seal bags or pouches to prevent wrinkles in the end seals to insure air-tight packages.
2. Statement of the Prior Art
In the art of automatically forming, filling and sealing pouches or packages, one approach is to feed a film around a forming collar into a tubular shape about a vertical forming tube. A vertical seal is made in the film and horizontal sealing dies seal the lower end of the film tube. A product is fed down the tube and into the formed pouch. The horizontal sealing dies then seal the film tube to form the upper end of the filled pouch and the lower end of the next pouch and a cutter removes the formed-filled-sealed pouch from the tube. Apparatus of this type is illustrated in U.S. Pat. No. 4,277,302.
In apparatuses of this type, it is desirable to prevent wrinkles in the horizontal end seals of the pouch to insure that the pouch is air tight. This is particularly true when outer pouches are formed around plastic bags of liquid and the completed pouch with its inside liquid bag are heat sterilized. There can be no air leaks in the outer pouch and thus all wrinkles in the film tube have to be removed when making the horizontal seals.